Medicament delivery device

ABSTRACT

The present invention relates to a medicament delivery device comprising a drive means configured to act on a medicament container for expelling a medicament; a holding means configured to hold said drive means in a pre-tensioned state; an activation means configured to interact with said holding means for releasing said drive means from the pre-tensioned state; wherein the device further comprises feedback means configured to interact both with said holding means and with said drive means for generating an audible and/or tactile and/or visual signal indicating that the medicament has been completely expelled.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 15/994,381, filed May 31, 2018, which is a continuation of U.S.patent application Ser. No. 15/480,820, filed Apr. 6, 2017, which is acontinuation of U.S. patent application Ser. No. 13/650,708, filed Oct.12, 2012, now U.S. Pat. No. 9,662,452, which is a continuation of U.S.patent application Ser. No. 13/636,241 filed Oct. 12, 2012, now U.S.Pat. No. 9,199,038, which is a U.S. National Phase Application pursuantto 35 U.S.C. § 371 of International Application No. PCT/SE2011/050236filed Mar. 23, 2011, which claims priority to U.S. Patent ApplicationNo. 61/319,453 filed Mar. 31, 2010 and Swedish Patent Application No.1050307-6 filed on Mar. 31, 2010. The entire disclosure contents ofthese applications are herewith incorporated by reference into thepresent application.

FIELD OF INVENTION

The present invention relates to a medicament delivery device and inparticular to an improved, more user-friendly, automatic medicamentdelivery device providing an audible, tactile or visual confirmation toa user when an injection has been made.

BACKGROUND

Many medicament delivery devices are developed for self-administration,i.e. a user performs the medicament delivery her-, or himself. Thisrequires a medicament delivery device which is as safe to use and aseasy to handle as possible. In order to meet these requirements, therisk of human errors must be minimized, the number of actions needed tobe performed in order to receive a dose need to be reduced and thedevice must be intuitive and ergonomic to use. Thus, in order tominimize the risk of human errors, it is desirable to have the device aspre-assembled as possible.

Document EP 1349590 B describes an injector having a number of featuresthat facilitate the handling of the injector. The penetration andinjection is performed manually by simply pressing the proximal end of aneedle shield against the delivery area, causing the shield to move in adistal direction, enabling the needle to penetrate the injection areaand thereafter initialize the injection process. When the injection isperformed the injector is withdrawn whereby a needle shield extractsaround the needle in a locked way.

Other aspects of injectors are the human aspect of handling the injectorregarding how it is held during operation. a general aim is to have thepatient holding the injector in an ergonomic way that may permit thepenetration and injection in different locations on the body, such asaround the waist and also on the backside of the waist and/or in thebuttocks of the patient. Sometimes the patient does not see the injectorat those locations and need to be able to hold the injector withouthaving to change grip. By removing the action of pushing a button or thelike, the patient is free to hold the device as he desires and feelscomfortable.

It is considered important for the patient to receive a confirmationthat the injection has been made, in particular in instances when aninjector is used where the patient does not see the injector, e.g. suchas around the waist and also on the backside of the waist and/or in thebuttocks of the patient.

SUMMARY

The object of the present invention is to provide a medicament deliverydevice that is reliable and easy to use when handling and activating,this is achieved by a medicament delivery device comprising a drivemeans configured to act on a medicament container for expelling amedicament; a holding means configured to hold said drive means in apre-tensioned state; an activation means configured to interact withsaid holding means for releasing said drive means from the pre-tensionedstate; wherein the device further comprises feedback means configured tointeract both with said holding means and with said drive means forgenerating an audible and/or tactile and/or visual signal indicatingthat the medicament has been completely expelled.

According to another aspect of the invention the device furthercomprises a tubular housing having a proximal end and an opposite distalend.

According to a further aspect of the invention the activation means is atubular activation member slidably and coaxially arranged in relation tothe tubular housing.

According to yet another aspect of the invention the device furthercomprises a container holder coaxially arranged within the tubularactivation member and fixedly attached to the tubular housing.

According to yet a further aspect of the invention the medicamentcontainer is arranged within said container holder and wherein saidmedicament container comprises a pre-determined volume of medicament, aslidable stopper and a delivery member.

According to yet an aspect of the invention the drive means comprises aplunger rod and a first resilient member which is pre-tensioned arrangedwithin the plunger rod and wherein said plunger rod is arranged to be incontact with the slidable stopper within the medicament container.

According to another aspect of the invention the holding means are atubular extension part fixedly connected to the distal end of thetubular housing and a tubular operation member which is interactivelyconnected both to the tubular extension part and to the tubularactivation member, such that when said tubular activation member ispressed against a delivery site said tubular operation member is rotatedin relation to said tubular extension part whereby said drive means arereleased from the pre-tensioned state for exerting a pressure on theslidable stopper and thereby expelling the medicament.

According to a further aspect of the invention the feedback means is alongitudinally extending signal generating member interactivelyconnected to said tubular extension part and to said drive means, suchthat when the plunger rod is completely released from the tubularextension part and the longitudinally extending signal generatingmember, the longitudinally extending signal generating member isreleased from said tubular extension part and displaced distally by aremaining force of the first resilient member for generating an audibleand/or tactile and/or visual signal indicating that the medicament hasbeen completely expelled.

According to a still further aspect of the invention, the tubularoperation member comprises a first co-acting means interactivelyconnected to a corresponding first co-acting means of the tubularactivation member and a second co-acting means interactively connectedto a corresponding second co-acting means of the tubular extension part;the plunger rod comprises a releasable engaging means interactivelyconnected to the corresponding second co-acting means of the tubularextension part and a proximal end wall being in contact with theslidable stopper; the longitudinally extending signal generating memberis releasable arranged on an inner surface of the tubular extensionpart; and wherein the first resilient member has a first end abuttingthe proximal end wall of the plunger rod and a second end abutting atransversal wall of the signal generating member.

According to another aspect of the invention, the second co-acting meanscomprises a groove on an inner surface of the tubular operation memberand the corresponding second co-acting means of the tubular extensionpart comprises a resilient tongue, having a radial inward protrusion.

According to a yet another aspect of the invention, the releasableengaging means comprises a groove on an outer surface of the plunger rodreleasable engaged to the radial inward protrusion of the resilienttongue adapted to hold the drive means in the pre-tensioned state.

According to a yet a further aspect of the invention, the firstco-acting means comprise a groove on an outer surface of the tubularoperation member and the first corresponding co-acting means comprise aradial inward extending protrusion on the distal end of the innersurface of the tubular activation member, such that the radial inwardextending protrusion is adapted to be guided within the groove on anouter surface of the tubular operation member forcing the tubularoperation member to rotate when the tubular activation member isdistally moved, whereby the resilient tongue is flexed radial outwardinto a groove on the inner surface of the tubular operation member andthe radial inward extended protrusion is disengaged from the groove onthe outer surface of the plunger rod such that the drive means arereleased from the pre-tensioned state.

According to another aspect of the invention, the signal generatingmember is an elongated u-shaped bracket comprising a transversal walland two longitudinally extending flexible arms provided with angledsupport members extending radially outward, and wherein said supportmembers are adapted to rest on an annular proximal end of the tubularextension part when the drive means are in the pre-tensioned state.

According to a further aspect of the invention, the transversal wall ofthe U-bracket is arranged at a predetermined distance D from an innerdistal surface of said tubular extension part when the drive means arein the pre-tensioned state.

According to yet another aspect of the invention, the audible signal isgenerated for confirming that a medicament delivery has been performedwhen the distal end of the plunger rod has passed the supportingmembers, such that the longitudinally extending flexible arms, with thesupport members, are released and allowed to move in a radial inwarddirection, enabling the U-bracket to move the predetermined distance Din the distal direction by a remaining force exerted by said firstresilient member, whereby the transversal wall of the bracket hits theinner distal surface of said tubular extension part.

According to yet a further aspect of the invention, the transversal wallof the U-bracket comprises a distally extending protrusion and thedistal surface of the tubular extension part comprises a through hole,such that when the transversal wall of the U-bracket hits the innerdistal surface of said tubular extension part, the distally extendingprotrusion passes through the through hole and extends distally apredetermined distance over the outer surface of said tubular extensionpart for generating a tactile signal.

According to another aspect of the invention, the distally extendingprotrusion has a bright and/or different colour than the rest of thedevice for generating a visual signal.

By the term automatic medicament delivery device, is herein meant amedicament delivery device adapted to deliver a medicament without auser having to press a push button or activation member, but insteadonly by pressing the proximal end of the medicament delivery deviceagainst the delivery site.

In automatic medicament delivery device it is considered, as mentionedabove, important for the patient to receive a confirmation that thedelivery has been made, in particular when the medicament deliverydevice is used where the patient does not see the medicament deliverydevice, e.g. such as around the waist and also on the backside of thewaist and/or in the buttocks of the patient. Therefore, a signal i.e. anaudible sound, and/or a tactile signal, and/or a visual signal, or acombination thereof is generated in direct temporal relationship to thephysical actuation of the medicament container, in order to expel themedicament from the medicament container.

The medicament delivery device according to the present inventionpresents a number of advantages. There is a high degree of functionalityand automation, which remove unnecessary components and actions fordelivering a medicament.

Also an important safety aspect is met since, during withdrawal, thetubular activation member is pushed out and covers the delivery membere.g. a needle, and also locks in the extended state, thereby preventingunintentional needle sticks.

These and other aspects of and advantages with the present inventionwill become apparent from the following detailed description and fromthe accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

In the following detailed description of the invention, reference willbe made to the accompanying drawings, of which

FIG. 1a -FIG. 1c shows perspective views of different components of themedicament delivery device.

FIG. 2a -FIG. 2d shows perspective views of different states of themedicament delivery device.

FIG. 3 illustrates a plunger rod and audio-tacit-visual signalgenerating member assembly.

FIG. 4a -FIG. 4c illustrates the components of the audio-tacit-visualsignal signal generating member-, and plunger rod assembly.

FIG. 5 shows a perspective view of a driving means comprised in thepresent invention.

FIG. 6a -FIG. 6c shows a side view of the tubular housing and theaudio-tacit-visual signal generating member in operation,

FIG. 7-FIG. 11 show side views along the longitudinal axis of themedicament delivery device according to an embodiment of the presentinvention, illustrating different states of an injection procedure.

DETAILED DESCRIPTION

In the present application, when the term “distal part/end” is used,this refers to the part/end of the delivery device, or the parts/ends ofthe members thereof, which is/are located the furthest away from themedicament delivery site of the patient. Correspondingly, when the term“proximal part/end” is used, this refers to the part/end of the deliverydevice, or the parts/ends of the members thereof, which, is/are locatedclosest to the medicament delivery site of the patient.

FIG. 1a illustrates, in perspective, a tubular housing 20 of anexemplary medicament delivery device 1. The tubular housing 20 having aproximal end 11 and an opposite distal end 12. The tubular housing 20further comprises a protrusion (not illustrated) on its inner wall. Theprotrusion is adapted for receiving a recess 36 of an activation means,such as a tubular activation member 30 (see FIG. 1b ). The recess 36 ofthe tubular activation member 30 is used for locking the tubularactivation member 30, inside the tubular housing 20, when the tubularactivation member 30 is in its most proximal position, after aninjection has been made. In an exemplary embodiment there are twoprotrusions (not illustrated), one on each side of the inner wall of thetubular housing 20, and correspondingly two recesses 36 of the tubularactivation member 30. The tubular housing 20 further comprises acontainer holder 50 which is coaxially arranged and fixedly attachedwithin the tubular housing 20 for lodging a medicament container 80 (seeFIG. 1c ). The medicament injection device 1 further comprises a tubularextension part 22, being coaxially arranged and fixedly attached to thedistal end 12 of the housing preferably by a flexible tongue 15 engagingwith a corresponding ledge 23 (see FIG. 5) of the tubular extension part22.

FIG. 1b illustrates the tubular activation member 30 of the medicamentinjection device 1. The tubular activation member 30 having an annularcontact member 31 and a corresponding first co-acting means 35, which inan exemplary embodiment is a protrusion. In an exemplary embodiment ofthe invention there are two corresponding first co-acting means 35 whichare used for activating the medicament delivery device 1 as will bedescribed in detail below. In the figure is in particular illustrated aguiding means 34 which is adapted to cooperate with a correspondingguiding rod (not shown) at the interior of the tubular housing 20, withthe purpose to prevent that the tubular activation member 30 may rotatein relation to the tubular housing 20 and to allow the tubularactivation member 30 to move in the axial direction in relation to thetubular housing 20. In a preferred embodiment of the invention there aretwo guiding means 34 and correspondingly two guiding rods (not shown).According to an embodiment of the invention, a second resilient member24 (see FIG. 1c ), which in an exemplary embodiment is a tension spring,is arranged at the proximal end of the tubular activation member 30 formoving it in a proximal direction. The cut-out/recess 36 is, when themedicament injection device 1 is positioned in its final position inorder to prevent unintentional availability of a proximal needle end 61(see FIG. 1c ), engaging with a corresponding protrusion (notillustrated) of the tubular housing 20.

FIG. 1c illustrates the interior of the medicament delivery device 1further comprising the second resilient member 24 arranged in relationto the tubular activation member 30 for moving it in a proximaldirection from a non-activated position to an activated position wherebythe annular contact member 31 is in contact with the proximal end of thehousing 20 when the medicament injection device 1 is in non-activatedstate and whereby the annular contact member 31 is at a predetermineddistance from the proximal end of the housing when the medicamentinjection device 1 is in activated state. The medicament container 80 isarranged within the container holder 50 and has a predetermined volumeof medicament, a slidable stopper 83 and a delivery member. In anexemplary embodiment of the invention the medicament container 80 is asyringe provided with a needle 61 as the delivery member, however theinvention should not be limited to this, other embodiments could includea medicament cartridge having a membrane 82, or the like where adelivery member can be adapted. In the medicament delivery device 1 isalso included a tubular operation member 100 (see FIG. 5) comprising asecond co-acting means 101, 102 interactively connected to acorresponding first co-acting means 35 of the tubular activation member30 (see FIG. 1b ), drive means comprising a plunger rod 90 and a firstresilient member 91 arranged within the plunger rod. The plunger rodcomprises a releasable engaging means 94 as a cut-out/recess (see FIG.4c ) interactively connected to a corresponding second co-acting means121 (see FIG. 5) of the tubular extension part 22. The first resilientmember 91 is in an exemplary embodiment of the invention a tensionspring. The proximal end 92 of the plunger rod 90 is in contact with theslidable stopper 83. The tubular operation member 100 (see FIG. 5) isrotatably and coaxially arranged on a proximal part of the tubularextension part 22 between the container holder 50 and an annular ledgeof the tubular extension part 22 at the distal end of the tubularhousing 20.

Together, the tubular extension part 22 and the tubular operation member100 form a holding means , for holding the drive means in apre-tensioned state prior to penetration. Upon actuation of theactivation means a feedback means interacts with the holding means andthe drive means to signal that a medicament has been completelyexpelled.

FIG. 2a -FIG. 2d show simplified perspective views of the medicamentdelivery device 1, where FIG. 2a illustrates an initial, non-activated,state of the medicament delivery device 1 having a cap 10. FIG. 2b showsan activated state of the medicament delivery device 1, where the cap 10is removed. FIG. 2c shows the penetration and injection state of themedicament delivery device 1 and finally FIG. 2d shows the medicamentdelivery device 1 in a final locked state. With references to FIG. 2 a,the medicament delivery device 1 comprises the tubular housing 20,having a proximal end and an opposite distal end. The medicamentinjection device 1 further comprises the tubular activation member 30which is slidably and coaxially arranged inside the tubular housing 20and comprises the proximal annular contact member 31. The cap 10comprises a distal end surface, abutting with the proximal end surfaceof the annular contact member 31 of the tubular activation member 30such that when the cap 10 is manually operated and detached, it allowsthe tubular activation member 30 to be moved by the force from thesecond resilient member 24 (FIG. 1c ) from its non-activated position toits activated position.

FIG. 2b show the medicament delivery device 1 when it is ready for use.When a user is about to perform a medicament delivery e.g. an injectionhe/she presses the proximal end, i.e. the annular contact member 31,against the delivery site e.g. an injection site. The tubular activationmember 30 is then moved in the distal direction, in relation to thetubular housing 20, and during the relative movement when having amedicament delivery device as an injection device, then a needle 61manually penetrates the skin. When the tubular activation member 30 isabout to reach its most distal position in relation to the tubularhousing 20 the medicament delivery is performed. A medicament deliveryis automatically performed when the tubular activation member 30, beingin an activated position, is moved in a distal direction in relation tothe tubular housing 20, to a delivery state position, where the annularcontact member 31 is close to the proximal end 11 of the tubular housing20.

FIG. 2c illustrates when the delivery is made, then the user removes themedicament delivery device 1 from the delivery site, thereby allowingthe tubular activation member 30 to move in the proximal direction inrelation to the tubular housing 20, by the force exerted by the secondresilient member 24 and finally reaches a final state; the locked state.

FIG. 2d illustrates the medicament delivery device 1 in its final andlocked state, wherein the tubular activation member 30 once more is inits most proximal position, as illustrated. in this state the proximalpart of the tubular activation member 30 fully protects the deliverymember 61 and the tubular activation member 30 is also locked, by thecut-out/recesses 36 (see FIG. 1b ) in the distal end of the tubularactivation member 30, engaging with the protrusions (not illustrated) ofthe tubular housing 20, in the final position in order to preventunintentional availability of the delivery member 61.

FIG. 3 illustrates various aspects of the feedback means, such as asignal generating member 110 and its implementations (see also FIG. 4a-FIG. 4c ). In FIG. 3 is illustrated an embodiment of the inventioncomprising the signal generating member 110 adapted to generate anaudible and/or tactile and/or visible injection confirmation signal upona performed medicament delivery, wherein the medicament deliveryconfirmation signal is generated when the drive means changes state froma pre-tensioned state wherein the first resilient member is pretensionedarranged within the plunger rod and the plunger rod is engaged to thetubular extension part, to a released state wherein the plunger rod iscompletely released from the tubular extension part and is no longer incontact with the signal generating member.

FIG. 4a -FIG. 4c illustrates a side view and perspective views,respectively, of the signal generating member 110 according to anexemplary embodiment of the invention. In the illustrated embodiment,the signal generating member 110 is an elongated u-shaped bracket,provided with at least two elongated arms 111, directed in the proximaldirection, and a lower part, a distal transversal end wall, 112 directedin the distal direction of the medicament delivery device, when arrangedwithin the tubular extension part 22. The signal generating member 110may be made from metal, plastic, or any combination of these materials.

FIG. 4c is a perspective, and partly exploded, view of the signalgenerating member 110 in relation to the plunger rod 90 and the firstresilient member 91. The upper parts of the arms 111 are provided withangled support members 113 extending in essentially radial outwarddirections with regard to a longitudinal axis of the u-bracket 110. Theu-bracket 110 is adapted to enclose at least a part of the plunger rod90 and the first resilient member 91, and the support members 113 areadapted to rest on an annular surface on the proximal end of the tubularextension part 22 when the drive means are in a pre-tensioned state,i.e. the opening 94 of the plunger rod 90 is engage with a radial inwardprojected protrusion (not shown) of a flexible tongue 121 of the tubularextension part 22.

When the drive means is in the pre-tensioned state, the distal end ofthe u-bracket 110 is arranged at a predetermined distance “D” (see FIG.6a ) from an inner distal surface of said tubular extension part 22 andwhen the drive means are in the released state, the distal end of theu-bracket 110 is in contact with the inner distal surface of saidtubular extension part 22. The audible and/or tactile and/or visibleconfirmation signal is generated when the distal end of the u-bracket110 hits and contacts the inner distal surface of the tubular extensionpart 22 by a remaining force exerted by said first resilient member 91.Thus, during the delivery procedure, when the distal end of the plungerrod 90 passes by the supporting members 113, the arms 111 with thesupport members 113 are released and allowed to move in a radial inwarddirection, due to a pre-tension of the arms 111, enabling the u-bracket110 to move in the distal direction and the signal, typically an audiblesound and/or a visual signal and/or a tactile signal is generated, whenthe u-bracket 110 hits the distal end of the tubular extension part 22.In the pre-injection state the u-bracket 110 is arranged such that thearms 111 are positioned in a space along the plunger rod 90 between theplunger rod 90 and the tubular extension part 22 enclosing the plungerrod 90. The support members 113 must have an extension in the radialoutward direction that exceeds the radial extension of the space betweenthe plunger rod 90 and the inner wall of the tubular extension part 22to secure that the signal generating member 110 is not released priorthe plunger rod 90 has moved away from between the arms 111. the outerdistal surface of the distal transversal end wall 112 may further have aprotrusion (not illustrated), adapted to be guided through an opening,typically a through hole (also not illustrated) of the distal end wallof the tubular extension part 22 and extends distally a predetermineddistance over the outer surface of said tubular extension part 22. In anexemplary embodiment of the invention, the distally extending protrusionhas a bright and/or different colour than the rest of the device forgenerating a visual signal. Thus, said protrusion will enable both atactile and a visual signal when the u-bracket 110 hits the distal endof the tubular extension part 22.

FIG. 5 illustrates the drive means as well as the holding means, whereinthe holding means comprises the tubular operation member 100 and thetubular extension part 22. The above-mentioned first correspondingco-acting means 35 are at least one inwards extending protrusion (seeFIG. 1b ) on the distal end of the inner surface of the tubularactivation member 30 and the first co-acting means are at least onegroove 101, 102, 103 on an outer surface of the tubular operation member100, such that said radial inwards extending protrusion 35 is adapted tobe guided within the at least one groove 101, 102, 103, forcing thetubular operation member 100 to rotate when the tubular activationmember 30 is axially moved. A second co-acting means 105 for holding theplunger rod 90 and the first resilient member 91 in the pre-tensionedstate comprises at least one groove 105 of the tubular operation member100 and engages with a flexible tongue 121 on the tubular extension part22, which locks the plunger rod 90 by the radial inwards extendingprotrusion (not shown) of the flexible tongue 121 and engaging with theopening 94 of the plunger rod 90. When the tubular operation member 100is rotated, at least one groove 105 of the tubular operation member 100allows the radial inwards extending protrusion of the flexible tongue121 to radial extension, thereby releasing the engagement between theprotrusion and the opening 94 of the plunger rod 90, thus releasing theplunger rod 90, exerted by the force of the first resilient member 91,in a proximal direction.

The medicament delivery device 1 further comprises a locking meansinteractively connected to the tubular activation member 30. The lockingmeans is preferably at least one ledge 106 on an annular surface of thetubular operation member 100 and a corresponding locking means are atleast one protrusion 95 on an outer surface of the tubular extensionpart 22, such that said at least one protrusion 95 is abutting said atleast one ledge 106 holding the tubular operation member 100 rotatablefixated to the tubular extension part 22.

FIG. 6a -FIG. 6c illustrates simplified side views of the distal part ofthe medicament delivery device 1 according to the present invention. Thepurpose of these figures is to briefly describe and illustrate theimportant features required to achieve the stated objects. In thefigures are shown the tubular extension part 22 that partly encloses thedrive means, i.e. the plunger rod 90 and the first resilient member 91,and the signal generating member 110.

In FIG. 6a the medicament delivery device 1 is ready for use, whereinthe signal generating member 110 is at a predetermined distance “D” fromthe inner distal surface of the tubular extension part 22.

In FIG. 6b the delivery procedure is initiated and the plunger rod 90moves in the proximal direction forcing the slidable stopper 83 (notshown) to expel the medicament via the delivery member 61. When thedistal end of the plunger rod 90 has passed the proximal part of thesignal generating member 110 the arms 111 of the signal generatingmember 110 flexes inwards allowing the signal generating member 110 tomove in the distal direction, resulting in that a sound, and/or atactile signal and/or a visual signal is generated when the signalgenerating member 110 contacts the inner distal surface of the tubularextension part 22. This is illustrated by FIG. 6 c.

FIG. 7-FIG. 11 show side views along the longitudinal axis of themedical delivery device 1. For sake of simplicity only features relevantfor describing the signal generation are indicated; in addition somemain parts of the medical delivery device 1 are indicated in FIG. 7-FIG.11.

FIG. 7 shows the medicament delivery device in an initial state wherethe cap 10 is still attached to the medicament delivery device. Thecontainer 80 is arranged within the medicament delivery device having apredetermined volume of medicament and also provided with a deliverymember 61 and a slidable stopper 83 at its distal end. The secondresilient member 34 is arranged in the proximal end of the medicamentdelivery device applying a force to the tubular activation member 30 inthe proximal direction. The plunger rod 90 has a proximal end in contactwith the slidable stopper 83 and encloses, at least partly, the firstresilient member 91 which is adapted to apply a force to the plunger rod90 in the proximal direction. The distal part of the plunger rod 90 isarranged in the tubular extension part 22 in combination with the signalgenerating member 110. In the most distal part of the medicamentdelivery device 100 is indicated the distance “D”, i.e. the“sound-generating” distance between the distal part of the signalgenerating member 110 and the inner distal surface of the tubularextension part 22.

FIG. 8 shows the medicament delivery device in the final locked state,where the tubular activation member 30 is locked in its proximalposition, protecting the delivery member 61.

FIG. 9 shows the medicament delivery device where the cap 10 has beenremoved from the medicament delivery device resulting in that thetubular activation member 30 is moved forward due to the forces exertedby the second resilient member 24. In the figure is shown in greaterscale the proximal part of the signal generating member 110 and itssupport members 113.

FIG. 10 shows the medicament delivery device where the tubularactivation member 30 is forced in the distal direction resulting in thatthe plunger rod 90 is released to be able to apply forces to theslidable stopper 83 resulting in that the medicament is delivered. Inthe figure is shown in greater scale the proximal part of the signalgenerating member 110 and its support members 113 and also the mostdistal part of the medicament delivery device.

FIG. 11 shows the medicament delivery device where the delivery has beenmade. The plunger rod 90 has now forced the slidable stopper 83 to expelall medicament from the container 80 through the delivery member 61.When the distal part of the plunger rod 90 passes by the distal part ofthe signal generating member 110 the arms 111 are allowed to moveinwards due to the pre-tension of the arms (illustrated by the upperin-zoomed part) and the signal generating member 110 is released andmoves thereby in the distal direction generating a signal, when reachingthe distal end surface of the tubular extension part 22 (illustrated bythe lower in-zoomed part).

Thus is illustrated a signal generating member 110 provided with twoarms 111. As indicated above, a higher number of arms is naturallypossible within the scope of the present invention as defined by theappended claims. if a higher number of arms is considered, e.g. three orfour, it is important that they all are pre-tensioned such that theyexert radially inward directed forces and also that they are evenlydistributed in a cross-sectional plane of the signal generating member110 in order to securely hold drive means in the pre-tensioned state.

With references mainly to FIG. 7 to FIG. 11 the operation of themedicament delivery device 1 will now be described in more detail. Inthe pre-tensioned state, the at least one protrusion 95 is abutting theledge 106 and the groove 105 is not aligned with the flexible tongue 121that is preventing release of the plunger rod 90. When the cap 10 isremoved the medicament delivery device 1 is ready for use. The tubularactivation member 30 is now in its most proximal position and themedicament delivery device 1 is ready for use. The tubular activationmember 30 is forced in the distal direction by the user and theprotrusion 35 is moved along the groove from position 101 to position102 achieving an anticlockwise rotation of the tubular operation member100, seen from the distal end. During the rotation of the tubularoperation member 100 the protrusion 95 is moved along the ledge 106 andfinally comes off the ledge 106. Alignment of groove 105 with flexibletongue 121 enables the release of the pre-tensioned plunger rod 90 tomove in the proximal direction, by the force exerted by the firstresilient member 91, and to apply forces to the slidable stopper 83 thatis forced to move in the proximal direction and the medicament is thusdelivered. When the medicament has been delivered and the medicamentdelivery device is removed from the delivery site, the tubularactivation member 30 is forced in the proximal direction, by means ofthe second resilient member 34 and the locking means, e.g. a flexibletongue 104 (see FIG. 5), on the at least one groove of the tubularoperation member 100 which locks the radially inwards extendingprotrusion 35 when the radially inwards extending protrusion 35 is movedover the tongue 104. The medicament delivery device 1 further comprisesa locking means interactively connected to the tubular activation member30. The locking means is a flexible tongue 104 on the at least onegroove of the tubular operation member 100 which locks the radiallyinwards extending protrusion 35 when said radially inwards extendingprotrusion 35 is moved over the tongue 104.

The generation of the signal functions as follows. When the drive meansis in the pre-tensioned state, the distal end of the u-bracket 110 isarranged at a predetermined distance “D” (see FIG. 6a ) from an innerdistal surface of said tubular extension part 22 and when the drivemeans are in the released state, the distal end of the u-bracket 110 isin contact with the inner distal surface of said tubular extension part22. The audible and/or tactile and/or visible confirmation signal isgenerated when the distal end of the u-bracket 110 hits and contacts theinner distal surface of the tubular extension part 22 by a remainingforce exerted by said first resilient member 91. Thus, during thedelivery procedure, when the distal end of the plunger rod 90 passes bythe supporting members 113, the arms 111 with the support members 113are released and allowed to move in a radial inward direction, due to apre-tension of the arms 111, enabling the u-bracket 110 to move in thedistal direction and the signal, typically an audible sound and/or avisual signal and/or a tactile signal is generated, when the u-bracket110 hits the distal end of the tubular extension part 22. In thepre-injection state the u-bracket 110 is arranged such that the arms 111are positioned in a space along the plunger rod 90 between the plungerrod 90 and the tubular extension part 22 enclosing the plunger rod 90.The support members 113 must have an extension in the radial outwarddirection that exceeds the radial extension of the space between theplunger rod 90 and the inner wall of the tubular extension part 22 tosecure that the signal generating member 110 is not released prior theplunger rod 90 has moved away from between the arms 111. the outerdistal surface of the distal transversal end wall 112 may further have aprotrusion (not illustrated), adapted to be guided through an opening,typically a through hole (also not illustrated) of the distal end wallof the tubular extension part 22 and extends distally a predetermineddistance over the outer surface of said tubular extension part 22. In anexemplary embodiment of the invention, the distally extending protrusionhas a bright and/or different colour than the rest of the device forgenerating a visual signal. Thus, said protrusion will enable both atactile and a visual signal when the u-bracket 110 hits the distal endof the tubular extension part 22.

It is however to be understood that embodiments described above andshown in the drawings are to be regarded only as non-limiting examplesof the present invention and that may be modified within the scope ofthe appended patent claims.

1. A drive mechanism for use in a medicament delivery device, the drivemechanism comprising: a plunger rod having a longitudinal axis; a springbiasing the plunger rod in a proximal direction; and a holder having aproximal end and enclosing all but a proximal portion of the plungerrod, where the plunger rod is releasably fixed relative to the holder tomaintain the spring in a pre-tensioned state, wherein the holder has aresilient member positioned at the proximal end.
 2. The drive mechanismof claim 1, wherein the resilient member is configured to abut a distalend of a medicament container when the drive mechanism is assembled intothe medicament delivery device.
 3. The drive mechanism of claim 1,wherein the resilient member comprises a flexible arm.
 4. The drivemechanism of claim 3, wherein the flexible arm is arc-shaped.
 5. Thedrive mechanism of claim 2, wherein the resilient member comprises twoproximally directed arc-shaped flexible arms that are configured to flexradially outward relative to the longitudinal axis when engaged with adistal end of a medicament container when the drive mechanism isassembled into the medicament delivery device.
 6. The drive mechanism ofclaim 1, wherein the spring is positioned within a hollow portion of theplunger rod.
 7. The drive mechanism of claim 6, wherein the plunger rodhas an open distal end and a closed proximal end, where the proximal endis configured to engage and move a slidable stopper in a medicamentcontainer when the drive mechanism is assembled into the medicamentdelivery device and when the spring changes from the pre-tensioned stateto a released state.
 8. The drive mechanism of claim 1, wherein theplunger rod has an outer surface that is releasably engaged with aflexible tongue on the holder.
 9. The drive mechanism of claim 1,wherein the holder has two flexible tongues each comprising inwardlydirected protrusions and where a outer surface of the plunger rod hastwo cut-outs that are releasably engaged with the protrusions.
 10. Thedrive mechanism of claim 8, wherein the flexible tongue is biasedinwardly relative to the longitudinal axis when the spring is in thepre-tensioned state.
 11. The drive mechanism of claim 8, wherein theflexible tongue is configured to flex outwardly relative to thelongitudinal axis to release the spring from the pre-tensioned statewhen the drive mechanism is activated and to cause the plunger rod tomove axially relative to the holder in a distal direction.
 12. Anautomatic medicament delivery device comprising: a housing; a containerholder attached to a proximal end of the housing; and a drive mechanismas claimed in claim
 1. 13. The medicament delivery device of claim 12,wherein the holder further comprises a flexible tongue that is engagedwith an outside surface of the holder.
 14. The medicament deliverydevice of claim 13, wherein the flexible tongue comprises an inwardlydirected protrusion that engages with a cutout on the outside surfacewhen the flexible tongue is flexed radially inward when the spring is inthe pre-tensioned state.
 15. The medicament delivery device of claim 14,wherein the flexible tongue is configured to flex radially outward whenan activation member slidably positioned in the housing is moved axiallyin the distal direction relative to the housing causing the protrusionto disengage from the cutout.
 16. The delivery device of claim 12further comprising a container of medicament axially fixed within thecontainer holder and having a slidable stopper that is operativelyengaged with a proximal end of the plunger rod such that a release ofthe pre-tensioned spring that is positioned within a hollow portion ofthe plunger rod causes the plunger rod and the slidable stopper to moveaxially relative to the housing in a proximal direction to dispensemedicament from the container.
 17. The delivery device of claim 12further comprising an activation member slidably positioned relative tothe holder such that axial movement of the activation member in a distaldirection relative to the holder causes the holder to release theplunger rod which causes the pre-tensioned state of the spring to changeto a released state such that the spring forces the plunger axially in aproximal direction.
 18. The delivery device of claim 17, wherein thechange from the pre-tensioned state to the released state generates anaudible, tactile or visible signal to a user of the medicament deliverydevice.
 19. The drive mechanism of claim 12, wherein the holder isrotatably fixed relative to the plunger rod and the plunger rod has aradial space defined by an inner diameter and a proximal end
 20. Thedrive mechanism of claim 19, wherein the spring biases the proximal endof the plunger rod in a proximal direction during both the pre-tensionedstate and a released state.